I'm another one that has used Fusion from early on and has never once HAD to upgrade because of a new MacOS, though maybe for better support for a new Windows version. With the APFS change I am not going to take any chances. I will be upgrading most of my utility type apps this time around. I too used Parallels at first and have gone back to check them out periodically, but Fusion is so much less invasive on the Mac side. I also need to use a lot of goofy I/O devices via USB and even USB>Serial adapters and Fusion has always been much more reliable for that. Add that I could port machines between Fusion and Workstation and even ESX and it's a no brainer.